1. Industrial Field of the Invention
The present invention relates to a structure for connecting electrodes of a motor unit and a motor driver unit which is a power circuit for the motor unit in an electric power drive vehicle, so that the motor unit and the motor driver unit are electrically connected to each other.
2. Description of the Prior Art
In a device employing a conventional structure for connecting electrodes of a motor unit and a motor driver unit, the motor unit 1 is located on the right side of the device in FIG. 4. A motor 3 is secured in a cylindrical casing 2 of the motor unit 1. The motor driver unit 6 covered with a cylindrical casing 5 is located on the left side of the device. The motor driver unit 6 is provided with an inverter circuit 4 for driving the motor 3. Both of the units are integrally coupled to each other by means of fixing screws 7. Connecting cables 9 of a driving coil 8 of the motor 3 are extended out of the casing 2. By way of example, as shown in FIG. 4, connection terminals 10 of the cables 9 are connected by nuts 13 to bolts 12 as connection terminals for the inverter circuit 4 which are provided on an outer peripheral surface of the casing 5 of the motor driver unit 6, with insulation bases 11 being interposed therebetween. Reference numeral 14 designates a motor drive shaft, numeral 15 designates a drive pulley, and numeral 16 designates a capacitor.
FIG. 5 illustrates another example of the conventional structure of electrically connecting the electrodes of the motor unit and the motor driver unit. More specifically, the connecting cables 9 of the driving coil 8 of the motor 3 are extended through the interior of the casing so as to be drawn out of the surface of the casing 5 for the motor driver unit 6 on the left side in the drawing. The connection terminals 10 of the connecting cables 9 are connected by the nuts 13 to bolts 17 as connection terminals for the inverter circuit 4 (not illustrated in FIG. 5), which bolts are provided on the left-side surface of the casing 5 with the insulation bases 11 being interposed therebetween. Secured to the other ends of the connection bolts 17 are electrode plates 19 comprising printed circuit boards on which power semiconductor elements are mounted, the electrode plates including terminal sections 18 to be connected to the inverter circuit 4. The connection cables 9 may be replaced by wiring metallic means 20 made of plate-like or linear conductors.
In any example of the conventional structure of connecting the electrodes of the motor unit and the motor driver unit to each other, which structure uses the connection cables 9 or the connection metallic means 20, the connection terminals 10 of the connection cables 9 or the connection metallic means 20 are connected by means of the nuts 13 to the bolts 12 or 17 provided as the connection terminals in the exterior of the casing 5 for the motor driver unit 6. With the above-described structures, a sufficient working efficiency is not obtained during the assembling or wiring. Also, it is necessary to overlay insulation covers on the connection terminals because the connection terminals are exposed to the exterior of the unit. The conventional structure possesses various problems such that the exposed connection terminals are factors of obstructing the unit from being reduced in size and weight, and further that the exposed connection terminals are not favorable from the viewpoint of design.
In view of the above-mentioned problems of the prior art, the present invention aims to improve a working efficiency during assembling and wiring, to reduce the unit in size and weight by providing connection terminals not to be exposed to the exterior of the unit, and to obtain a unit which is excellent in design at a low cost.